Pulpstone



United States Patent PULPSTONE James H. Perry, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application December 19, 1952, Serial No. 326,836

2 Claims. (Cl. 51--168) The invention relates to pulpstones, and in particular to an improved mounting therefor.

One object of the invention is to provide a simple and thoroughly practical improved mounting for a segmental pulpstone. Another object of the invention is to provide a pulpstone having outwardly flaring frustoconical clamping surfaces and inverted flanges for clamping the same. Other objects will be in part obvious and in part pointed out hereinafter.

The drawing is a sectional view through the improved pulpstone.

One embodiment of the invention has been illustrated in the drawings comprising a pulpstone in which a plurality of bonded abrasive segments 11 are arranged about the periphery of a reinforced concrete center portion 12. The concrete center portion 12 is reinforced by a network of interlocked metallic reinforcing rings 13. The abrasive segments 11 are anchored to the concrete center 12 by a plurality of studs 14 and 15, one end of which is screw threaded into the segments 11 and the other end embedded in the reinforced concrete center 12. This pulpstone may be of a well known type such as for example that shown in the prior U. S. Patent No. 2,421,886 to Wallace L. Howe and Lorenzo S. Washburn dated June 10, 1947, to which reference may be had for details of disclosure not contained herein. Suitable spaces of filling material 16 are provided between adjacent segments, such as for example that described in the prior U. S. patent to Larsson 2,054,177.

The pulpstone is assembled by suspending the reinforcing rings or network on end, then arranging segments on their side faces around the network 13 in successive rows with the studs 14 and 15 projecting be tween the rings of the network 13. Layers of filler material are placed between adjacent segments during assembly, after which concrete is poured into the upper end of the supporting mold to form the wheel center 12.

In a pulp grinding machine the logs are arranged with their axis substantially parallel to the axis of the pulpstone and are forced against the periphery of the pulpstone at a very high pressure so that a high power motor is required to drive the same. In the conventional mounting such as for example that shown in U. S. Patent No. 2,467,878 to H. W. H. Beth dated April 19, 1949, the side faces of the concrete center are tapered inwardly toward the periphery of the pulpstone and the mounting flanges are correspondingly tapered to clamp the stone in an operative position relative to the supporting spindle. In such a construction, the high pressure thrust of the logs being ground against the periphery of the pulpstone is taken up, in part, by the flange at a diametrically opposite point from the line of pressure. This pressure tends to force the stone away from the tapered flanges on the side adjacent to the logs being ground. In such a construction the thrust of the logs being ground on the wheel is transmitted through the abrasive segments and wheel center to the diametrically opposite portion thereof thus setting up undue strains within the pulpstone.

It is the main object of this invention to overcome this ditficulty and to provide frusto-conical end faces 17 and 18 on the reinforced concrete center 12 in which the faces flare outwardly toward the periphery of the pulpstone. Annular rings of gasket material 19 and 20 are fastened to the frusto-conical faces 17 and 18.

A plurality of centering screws or bolts 25 are screw threaded into nuts embedded within the concrete center portion 12 to facilitate centering the pulpstone 10 relative to a supporting and driving spindle 26.

The supporting spindle 26 is provided with threaded portions 27 and 28, one of which is a right hand thread and the other a left hand thread. A pair of mounting flanges 29 and 30 are screw threaded onto the thread portions 27 and 28. The flanges 29 and 30 are provided with inwardly projecting hub portions 31 and 32 and have outer plane faces 33 and 34 which project only a slight distance from the side faces of the pulpstone 10, thus forming a more compact construction with less external projection therefrom.

The flanges 29 and 30 are provided with mating frustoconical faces which mate with the frusto-conical faces of the gaskets 19 and 20. The flanges 29 and 30 are then tightened into position to lock the pulpstone 10 into position on the spindle 29. Due to the tapering of the inverted flanges toward the center, the thrust of the logs being forced against the periphery of the pulpstone 10 will be taken up by the flanges at a point adjacent to the line of contact between the logs and wheel and will not be transmitted through the entire mass of the wheel.

It Will thus be seen that there has been provided by the invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a pulpstone having a plurality of bonded abrasive segments supported by a reinforced concrete center, an internal surface of revolution extending therethrough forming a central aperture, a wheel spindle extending through said aperture, a pair of clamping flanges screw threaded onto said spindle, an inwardly projecting hub portion on each of said flanges, an outwardly flaring fiusto-conical side face on each side of said pulpstone, and a mating outwardly flaring frusto-conical face on each of said flanges, said outwardly flaring surfaces serving to take up the grinding thrust on the periphery of the wheel between adjacent portions of the flanges.

2. In a pulpstone as claimed in claim 1, in combination with the parts and features therein specified in which the clamping flanges are each provided with a plane outer surface which is positioned in close proximity to the side faces of the pulpstone so as to form a compact mounting for the pulpstone.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,920,204 Larsson Aug. 1, 1933 2,205,296 Leafe June 18, 1940 2,467,878 Beth Apr. 19, 1949 FOREIGN PATENTS Number Country Date 325,888 Great Britain Mar. 3, 1930 

